1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Noralf Trønnes
4  */
5 
6 #include <linux/module.h>
7 #include <linux/slab.h>
8 
9 #include <drm/drm_atomic.h>
10 #include <drm/drm_atomic_helper.h>
11 #include <drm/drm_bridge.h>
12 #include <drm/drm_plane_helper.h>
13 #include <drm/drm_probe_helper.h>
14 #include <drm/drm_simple_kms_helper.h>
15 
16 /**
17  * DOC: overview
18  *
19  * This helper library provides helpers for drivers for simple display
20  * hardware.
21  *
22  * drm_simple_display_pipe_init() initializes a simple display pipeline
23  * which has only one full-screen scanout buffer feeding one output. The
24  * pipeline is represented by &struct drm_simple_display_pipe and binds
25  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
26  * entity. Some flexibility for code reuse is provided through a separately
27  * allocated &drm_connector object and supporting optional &drm_bridge
28  * encoder drivers.
29  *
30  * Many drivers require only a very simple encoder that fulfills the minimum
31  * requirements of the display pipeline and does not add additional
32  * functionality. The function drm_simple_encoder_init() provides an
33  * implementation of such an encoder.
34  */
35 
36 static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
37 	.destroy = drm_encoder_cleanup,
38 };
39 
40 /**
41  * drm_simple_encoder_init - Initialize a preallocated encoder with
42  *                           basic functionality.
43  * @dev: drm device
44  * @encoder: the encoder to initialize
45  * @encoder_type: user visible type of the encoder
46  *
47  * Initialises a preallocated encoder that has no further functionality.
48  * Settings for possible CRTC and clones are left to their initial values.
49  * The encoder will be cleaned up automatically as part of the mode-setting
50  * cleanup.
51  *
52  * The caller of drm_simple_encoder_init() is responsible for freeing
53  * the encoder's memory after the encoder has been cleaned up. At the
54  * moment this only works reliably if the encoder data structure is
55  * stored in the device structure. Free the encoder's memory as part of
56  * the device release function.
57  *
58  * FIXME: Later improvements to DRM's resource management may allow for
59  *        an automated kfree() of the encoder's memory.
60  *
61  * Returns:
62  * Zero on success, error code on failure.
63  */
64 int drm_simple_encoder_init(struct drm_device *dev,
65 			    struct drm_encoder *encoder,
66 			    int encoder_type)
67 {
68 	return drm_encoder_init(dev, encoder,
69 				&drm_simple_encoder_funcs_cleanup,
70 				encoder_type, NULL);
71 }
72 EXPORT_SYMBOL(drm_simple_encoder_init);
73 
74 static enum drm_mode_status
75 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
76 			       const struct drm_display_mode *mode)
77 {
78 	struct drm_simple_display_pipe *pipe;
79 
80 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
81 	if (!pipe->funcs || !pipe->funcs->mode_valid)
82 		/* Anything goes */
83 		return MODE_OK;
84 
85 	return pipe->funcs->mode_valid(pipe, mode);
86 }
87 
88 static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
89 				     struct drm_atomic_state *state)
90 {
91 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
92 									  crtc);
93 	bool has_primary = crtc_state->plane_mask &
94 			   drm_plane_mask(crtc->primary);
95 
96 	/* We always want to have an active plane with an active CRTC */
97 	if (has_primary != crtc_state->enable)
98 		return -EINVAL;
99 
100 	return drm_atomic_add_affected_planes(state, crtc);
101 }
102 
103 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
104 				       struct drm_atomic_state *state)
105 {
106 	struct drm_plane *plane;
107 	struct drm_simple_display_pipe *pipe;
108 
109 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
110 	if (!pipe->funcs || !pipe->funcs->enable)
111 		return;
112 
113 	plane = &pipe->plane;
114 	pipe->funcs->enable(pipe, crtc->state, plane->state);
115 }
116 
117 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
118 					struct drm_atomic_state *state)
119 {
120 	struct drm_simple_display_pipe *pipe;
121 
122 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
123 	if (!pipe->funcs || !pipe->funcs->disable)
124 		return;
125 
126 	pipe->funcs->disable(pipe);
127 }
128 
129 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
130 	.mode_valid = drm_simple_kms_crtc_mode_valid,
131 	.atomic_check = drm_simple_kms_crtc_check,
132 	.atomic_enable = drm_simple_kms_crtc_enable,
133 	.atomic_disable = drm_simple_kms_crtc_disable,
134 };
135 
136 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
137 {
138 	struct drm_simple_display_pipe *pipe;
139 
140 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
141 	if (!pipe->funcs || !pipe->funcs->enable_vblank)
142 		return 0;
143 
144 	return pipe->funcs->enable_vblank(pipe);
145 }
146 
147 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
148 {
149 	struct drm_simple_display_pipe *pipe;
150 
151 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
152 	if (!pipe->funcs || !pipe->funcs->disable_vblank)
153 		return;
154 
155 	pipe->funcs->disable_vblank(pipe);
156 }
157 
158 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
159 	.reset = drm_atomic_helper_crtc_reset,
160 	.destroy = drm_crtc_cleanup,
161 	.set_config = drm_atomic_helper_set_config,
162 	.page_flip = drm_atomic_helper_page_flip,
163 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
164 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
165 	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
166 	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
167 };
168 
169 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
170 					struct drm_plane_state *plane_state)
171 {
172 	struct drm_simple_display_pipe *pipe;
173 	struct drm_crtc_state *crtc_state;
174 	int ret;
175 
176 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
177 	crtc_state = drm_atomic_get_new_crtc_state(plane_state->state,
178 						   &pipe->crtc);
179 
180 	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
181 						  DRM_PLANE_HELPER_NO_SCALING,
182 						  DRM_PLANE_HELPER_NO_SCALING,
183 						  false, true);
184 	if (ret)
185 		return ret;
186 
187 	if (!plane_state->visible)
188 		return 0;
189 
190 	if (!pipe->funcs || !pipe->funcs->check)
191 		return 0;
192 
193 	return pipe->funcs->check(pipe, plane_state, crtc_state);
194 }
195 
196 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
197 					struct drm_plane_state *old_pstate)
198 {
199 	struct drm_simple_display_pipe *pipe;
200 
201 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
202 	if (!pipe->funcs || !pipe->funcs->update)
203 		return;
204 
205 	pipe->funcs->update(pipe, old_pstate);
206 }
207 
208 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
209 					   struct drm_plane_state *state)
210 {
211 	struct drm_simple_display_pipe *pipe;
212 
213 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
214 	if (!pipe->funcs || !pipe->funcs->prepare_fb)
215 		return 0;
216 
217 	return pipe->funcs->prepare_fb(pipe, state);
218 }
219 
220 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
221 					    struct drm_plane_state *state)
222 {
223 	struct drm_simple_display_pipe *pipe;
224 
225 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
226 	if (!pipe->funcs || !pipe->funcs->cleanup_fb)
227 		return;
228 
229 	pipe->funcs->cleanup_fb(pipe, state);
230 }
231 
232 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
233 						uint32_t format,
234 						uint64_t modifier)
235 {
236 	return modifier == DRM_FORMAT_MOD_LINEAR;
237 }
238 
239 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
240 	.prepare_fb = drm_simple_kms_plane_prepare_fb,
241 	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
242 	.atomic_check = drm_simple_kms_plane_atomic_check,
243 	.atomic_update = drm_simple_kms_plane_atomic_update,
244 };
245 
246 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
247 	.update_plane		= drm_atomic_helper_update_plane,
248 	.disable_plane		= drm_atomic_helper_disable_plane,
249 	.destroy		= drm_plane_cleanup,
250 	.reset			= drm_atomic_helper_plane_reset,
251 	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
252 	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
253 	.format_mod_supported   = drm_simple_kms_format_mod_supported,
254 };
255 
256 /**
257  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
258  * @pipe: simple display pipe object
259  * @bridge: bridge to attach
260  *
261  * Makes it possible to still use the drm_simple_display_pipe helpers when
262  * a DRM bridge has to be used.
263  *
264  * Note that you probably want to initialize the pipe by passing a NULL
265  * connector to drm_simple_display_pipe_init().
266  *
267  * Returns:
268  * Zero on success, negative error code on failure.
269  */
270 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
271 					  struct drm_bridge *bridge)
272 {
273 	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
274 }
275 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
276 
277 /**
278  * drm_simple_display_pipe_init - Initialize a simple display pipeline
279  * @dev: DRM device
280  * @pipe: simple display pipe object to initialize
281  * @funcs: callbacks for the display pipe (optional)
282  * @formats: array of supported formats (DRM_FORMAT\_\*)
283  * @format_count: number of elements in @formats
284  * @format_modifiers: array of formats modifiers
285  * @connector: connector to attach and register (optional)
286  *
287  * Sets up a display pipeline which consist of a really simple
288  * plane-crtc-encoder pipe.
289  *
290  * If a connector is supplied, the pipe will be coupled with the provided
291  * connector. You may supply a NULL connector when using drm bridges, that
292  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
293  *
294  * Teardown of a simple display pipe is all handled automatically by the drm
295  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
296  * release the memory for the structure themselves.
297  *
298  * Returns:
299  * Zero on success, negative error code on failure.
300  */
301 int drm_simple_display_pipe_init(struct drm_device *dev,
302 			struct drm_simple_display_pipe *pipe,
303 			const struct drm_simple_display_pipe_funcs *funcs,
304 			const uint32_t *formats, unsigned int format_count,
305 			const uint64_t *format_modifiers,
306 			struct drm_connector *connector)
307 {
308 	struct drm_encoder *encoder = &pipe->encoder;
309 	struct drm_plane *plane = &pipe->plane;
310 	struct drm_crtc *crtc = &pipe->crtc;
311 	int ret;
312 
313 	pipe->connector = connector;
314 	pipe->funcs = funcs;
315 
316 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
317 	ret = drm_universal_plane_init(dev, plane, 0,
318 				       &drm_simple_kms_plane_funcs,
319 				       formats, format_count,
320 				       format_modifiers,
321 				       DRM_PLANE_TYPE_PRIMARY, NULL);
322 	if (ret)
323 		return ret;
324 
325 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
326 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
327 					&drm_simple_kms_crtc_funcs, NULL);
328 	if (ret)
329 		return ret;
330 
331 	encoder->possible_crtcs = drm_crtc_mask(crtc);
332 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
333 	if (ret || !connector)
334 		return ret;
335 
336 	return drm_connector_attach_encoder(connector, encoder);
337 }
338 EXPORT_SYMBOL(drm_simple_display_pipe_init);
339 
340 MODULE_LICENSE("GPL");
341